Locking device for incandescent-electric-lamp bulbs.



L. DAVIS. LOOKING DEVICE FOR INCANDBSGBNT ELECTRIC LAMP BULBS. 7

APPLICATION FILED MAR. 15, 1909. Y Patented Sept. 7, 1909.

T0 all whom it may concern:

rues.

LEVI DAVIS, OF ALTON, ILLINOIS.

LOCKING. DEVICE FOR INCANIIESCEN'Q ELECTRIC-LAMP BULBS.

seas.

Specification'of Letters Patent. patgnte pl Sgpt, "Z, 1909,.

Application filed March 15, 1909. Serial No. 483,577.

for use in the sockets of incandescent electric lamps whereby theft of the lamp bulbs may be prevented. I

Figure Iis an elevation of an incandescent electric lamp having my locking device applied thereto. Fig. H is an enlarged view,

partly in elevation and partly in longitudinal section, illustrating my, improvement. Fig. III is a cross section taken on line III-III, Fig. II. Fig. IV is an elevationof the neckof a lamp bulbhaving a stop thereon adapted to receive my lelckmg device. Fig. V is a similar view to Fig. IV illustrating anothermanner of roducing the stop for the locking device. ig. VI is an enlarged elevation of the locking screw of my. de

,vice. Fig. 'VII is an end view of the locking 30 screw. Fig. VIII is an elevation of the key by which the locking screw may be operated. Fig. IX is an end view of the key shown in F ig. VIII; Fig. X is in part a longitudinal section through a modification of the ring of my locking device and a lamp bulb, and in part an elevation of theneck of a lamp bulb seated in the socket.

In the accompanying drawings: A. designates the socket of an incandescent electric.

lamp, this socket being provided atjits end with one or more slots or openings B, (see Fig. II.

G is a lam bulb having upon its neck the screw-three ed shell D adapted to be entiered into the socket A in the usual manner.

Referring now to my locking device, 1 designates a locking ring that isadapted to be fitted to the lamp socket A and which is provided ;with ascrew threaded aperture 2, and has at its lower end an annular flange 3 that the main body of the ring.

4 is a locking screwhaving a screw threadedbody 5 that enters into the aperture 2 in the locking ring, and a stem 6 that isadapted to protrude past the inner face of the locking face of the locking ring and into the socket A. The shank 7 of the locking screw is adapted to receive a key 9, shown in Figs. VIII and IX, and in order that the locking screw may be operated by the key, the shank is provided with a flattened side 8 which is adapted toreceive the flat face 10 within the socket of the locking key, (see Fig. IX,) the remainder of the said key socket being seg mental in shape.

The locking screw 4 of my device is adapted to be introduced into the locking ring of the device to such a degree" as to cause the stem of said screwto be moved inwardly to an extent sufiicient to position the end of the stem close to one of the threads upon the shell of the lamp bulb C. ,When thescrew is entered into the locking ring to the extent just stated, its stem occupies a position in the'path of travel of the stop d projecting from the thread of the lamp bulb shell, (Fig. IV.) Or, in lieu of said projecting stop, I may produce in the thread of the shell a recess d, (see Fig. V,) into which the stem of the locking screw may enter. The locking screw in its extension from the locking ring also passes through the opening B in the lamp socket, and as a consequence, the lamp socket serves to prevent rotation of said locking ring so that when the locking screw is in impingement with the stop portion of the lamp bulb, the locking ring is held from rotation upon the socket and removal of 'the lamp bulb from the socket is prevented due to the engagement of the locking screw with the stop portion of the lamp bulb shell.

To prevent the locking ring being slipped down on the socket, and onto the neck of the lamp bulb with the result of withdrawing the locking screw from the slot or opening in the'lamp socket, I provide the locking rin with an inwardly extending flange 3 which bears against the tapering neck of the lamp bulb, (as seen in Fig. II,) and by so doing permits of the lamp bulb holding the locking ring in its proper pdsitiou.

the" aperture 2' in the locking ring corre- I ,sponds in diameter to said body. This construction provides for the shank of the lockmg screw entering 1nto the aperture in the lockmg; ring, (as seen in Flgs. II and III,)

with a suflicient space around it to permit the introduction of the screw engaging end lit gagement with the shell of the lamp of the key 9 into said aperture when the screw is. wholly introduced into lockin e11];- u The shank of the screw is therefore unexposed when the lamp bulb is locked in the socket, and due to the peculiar shape of the shank of the locking screw, it is extremely diflicult to operate the locking screw Without the use of the key 9 provided especially for the operation of said screw, and which is not intended to fall into the hands of any one who might attempt theft of the lamp bulbs. 111 Fig. X, I have shown a modification in' which the locking-ring 1 is, instead of being-"provided with an inwardly extending flange 8, (as shown in Fig. IL) made of the proper width to permit of its being engaged by the lamp bulb when said bulb has been entered into the lamp socket, thereby causing the bulbto hold the locking ring from downward movement upon the socket to a degree suflicient to permit the escape of the locking screw 4 from the openingB' in the socket.

I claim:

1. The combination with an incandescent electric lamp socket and a bulb seated therein, of a ring fitted to said socket, and a lockiug member movable in said ring through. said socket into engagement with said bulb.

.2. The combination with an incandescent electric lamp socket and a bulb seated therein, of a ring fitted to said socket, and a locking screw in said ring extending through of the screw.

4. The combination with an incandescent.

'electric lamp socket and a lamp bulb having a screw threaded shell entering into said socket, of a ring fitted to said socket, and a locking member movable in said ring lnto engagement with said lamp bulb shell; said ring being arranged in engagement with said bulb at its lbwer end to prevent longitudinal movemen't thereof on said socket.

The combination with an incandescent electric lamp socket and a lam bulb having a screw threaded shell entering into said socket, of a ring fitted to said socket, and a locking member movable in said ring into enga ement with said lampbulb shell; said ring icing provided at its lower end with an inwardly extending flange for engagement with the lamp bulb to prevent longitudinal movement of the ring upon said socket.

LEVI DAVIS. In the presence of- I]. G. Cook,

E. M. HAmuNo'roN; 

